Formation tester



2 Shets-Sheet 1 L. S. CHAMBERS FORMATION TESTER April 6, 1954 Filed Nov. 12, 1948 April 6, 1954 s. CHAMBERS FORMATION TESTER X\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ W m m y@ HKU HVV/f/ /W/ wm f M im A m W w J H M s. EITIQ 6i; 5 m

,f///////// \\Ld^^/ af/ 7 @.747 /////////J,7//////// 8 l w|||| W/ s v 1 0 3 1 mmwo 66V 66 Z .NHUHIIIIHHHHHV HHH e Filed Nov. 12, 1948 Patented Apr. 6, 1954 UNITED STATES PATENT OFFICE FORMATION TESTER Lawrence S. Chambers, Los Angeles, Calif.

Application November 12, 1948, Serial No. 59,440

(Cl. Z55- 1.4)

6 Claims. 1

This invention relates to improvements in apparatus for sampling the fluids of earth formations, and particularly underground formations into which bore holes have been drilled.

It has been previously suggested to sample such formations by means of a sampler inserted through the drill pipe of a well and driven into the formation at the bottom of the bore. The sampler comprises a container which is connected to a punch which may be driven into the formation at the bottom of the well. Means are also provided for capturing the sample of fluid, passing through the conduit formed in the punch, in the container.

In constructing and operating such samplers, it has been found difficult to introduce the punch into certain formations, particularly hard formations, without fracturing the formation badly. This permits tlie drilling mud which is present in the well under high hydrostatic pressure to pass into the formation and into the sampling conduit. Contamination of the sample may result. Indeed, the fracture may be so excessive as to prevent successful sampling of the formation.

In the improvement of my invention, the sampling tube is in the form of a core barrel attached to a sample-receiving container which is lowered through the drill pipe from the surface. By employing a relatively thin-walled coring tube and providing a drilling end to the tube, the tube becomes a rotary core barrel or tube and may be drilled into the formation by rotary drilling methods with little or no fracture thereof. displacement of the formation. The tube takes the sample through perforations in the wall thereof and around the core in the tube. The sample passes into the sample-receiving compartment to which the coring tube is attached. In order to minimize the time taken in cperating my tool, I employ a sampler which may be introduced into the drill pipe after removing the kelly. The kelly is replaced and the sampler is circulated to bottom. The sampling core barrel tube is passed through the conventional core barrel bit and is drilled into the formation by employing conventional drilling technique.

When the drilling is completed, usually sun cient to advance the drill pipe about one foot,

is made under automatically controlled equilb- This is because there is but little lateral rium pressure conditions. It is important, in order to obtain a true sample of the formation fluid, that the flow of iluid be at a controlled rate and under controlled pressure. Since the formation fluid (especially if it is petroleum) is a multi-phase fluid including oil, gas, and sometimes water, if the fluid from the formation passes into a receiver at a high rate and at substantially lower pressure than the formation pressure, there will be a phase separation.

In the device of my present invention the formation iiuid flows under a balanced pressure and at a controlled rate into a container so that little or no phase separation need occur. The time taken for this sampling need be but a minute or two so that circulation of drilling mud and rotation of the drill pipe are interrupted only for a small period of time. The restriction in the time that circulation or rotation is i11- terrupted is often of vital importance, since, as is well known, in many cases the interruption of circulation and rotation or other movement of the pipe for any protracted period of time is highly dangerous and may result in sticking of the drill pipe due to settling of mud and cuttings in the quiescent column of mud even though highly efficient muds are employed. After the sample is taken the drill pipe is lifted, the pipe set in slips in the rotary table, the kelly is removed, an overshot is lowered into the drill pipe, and the sampler retrieved.

Thus, by employing a coring bit as a sampling tube and an automatic pressure balance during the sampling operation, I can avoid the difficulties which previous devices encountered in sampling formations arising from fracture thereof. A true sample may be taken and all this accomplished in a minimum of time and without the danger of the sticking of the drill pipe. By limitingthe time during which circulation or rotation is interrupted sticking of the drill pipe is avoided.

These and other objects of my invention will be apparent to those skilled in the art from the following description taken together with the drawings, in which Fig. 1 is an assembly view showing the sampler in position in a drill pipe, the drill pipe being shown in section;

Fig. 2 is a section of the lower end of the drill pipe and the sampler with the sampling piston at its initial position, and showing the clock, batteries, and wiring schematically;

Fig. 3 is a view similar to Fig. 2 with the valve pin removed;

Fig. 4 is a portion of the sampler and drill pipe immediately above the sections shown in Fig. 2;

Fig. 5 is a view similar to Fig. 4, corresponding to the condition shown in Fig. 3;

Fig. 6 is a section on line 5 5 of Fig. 5; and

Fig. 1 is a top of the section shown in Figs. 4 and 5.

The drill pipe I carries a conventional wire line coring bit 2. The sampler 3 is introduced into the drill pipe I after removal of the kelly,

the drill pipe being suspended in the slips of the rotary table with the core drill suspended above the bottom ci the hole. The kelly is replaced and the sampler is circulated to bottom by pumping mud into the drill pipe. Its arrival at the bottom, where it seats on the shoulder of the core bit shown at I2, is signalled by the rise in mud pump pressure.

lThe sampler is composed of a sampling core tube 4 carrying serrations or teeth 5 on its periphery at its lower end, also perforations 5 disposed throughout the length o the sampling core tube 4. The core tube is screwed into the lower end of conduit 5 positioned in the bottom portion of the sampler. Conduit 5 carries a beveled lower end 5 which forms a conical annulus with the core tube for purposes to be described later, and has a central bore I5. The conduit 8 carries an external shoulder I I which is seated upon the internal shoulder I2 of the core bit 2.

The conduit 5 is screwed into the tube I 3. The tube I3 carries a battery and clock chamber case I4 closed by a top plug I5 and a bottom plug I5 which is screwed into the fitting i1 which is in turn screwed into the internally threaded bore I5 of the conduit il. The tting I1 has a side port IS, and a central bore into which is clamped a frangible tube 2l which is sealed at its lower end 22. Positioned within the tube 2l is a cartridge of explosive 23 carrying a cap and insulated electric conductor wires 25 and 25. Wire 25 is grounded at 21, the insulated wire 25 passing through insulating bushing 25 in iitting I1 and through an insulating bushing 29 in the plug I5. Wire 25 is then connected to batteries 35 which are connected by wire 3| to contact arms 33 and 34 of clock 32. Contact 34 is grounded at 35. It will be observed that there is an annular recess 35 which connects the port I5 and the bore 25 to the chamber 31 within tube I3 above the plug I5.

Screwed into the top of tube I3 is plug valve fitting 38 carrying a central check valve 33 containing a downwardly opening port 42, a ball check valve in said port and a spring 5I urging the ball valve downwardly to closed position. Positioned above and communicating with the port 42 is a cross bore 43 carrying a plug 45, a spring 58, a ball check valve 49 to which is con nected a pin 55 carrying a bore 5I. The top of the plug 38 carries a vertical bore 52 in which a sliding pin 53 is positioned and which passes through the bore 5i to hold the ball check valve 49 from its seat 54. An additional port 55 is also provided in the top of the fitting 35.

The cylinder 55 is screwed onto the fitting 38 and carries a freely sliding piston 51 which makes a seal fit with the walls or" cylinder 56. A wire or line 53 is connected to the piston by a swivel 51 and to the pin 53. The cylinder 55 is screwed into the latch tting 53 carrying at its lower end a bore 55 into which is screwed a choke 6I having a small bore 5I' and a conical bore 62 in which is positioned a screen 63. Additional bores 54 4 are provided in the bottom of the tting 59 and these bores connect the interior of the cylinder 5B above the piston 5l with the exterior of the sampler and are closed by removable plugs 65.

The fitting 55 has a central bore 55 in which is positioned a flexible, helically wound, coiled tube 6i which is connected by a fitting 68 to the bore 55 at one end and at the other end by a fitting 59 to a bore 82' in tube 15. The tube 10 carries a conical wedge 1I and shoulder 1 I which will be described later.

Latehes 13 are pivotally positioned upon pivots 14 in slots in the wall of the latch fitting. The upper end of the latch 13 carries a recess 15 in which is seated a coil spring 15 connected at one end to the latch 'i3 and at its other end to the shoulder 11 depending from the fitting 59. The lower end of the latch is beveled at 13 as indicated for the purpose to be described later.

The tube 10 passes slidably through a bore 13 in the top of fitting 59. The upper end of the tube is connected to a plug inserted in the bottom of the cylinder 8|. The tube 15 also carries a central bore 52 which connects the llexible tube 51 and the chamber 82 in the cylinder 8i. rThe top of the cylinder 3| is closed by a plug 83 carrying a bore 86 closed by a plug 85 and also carries an overshot head 55 to which the overshot grapple 81 may be connected as in conventional overshot practice.

To prepare the sampler for insertion into the drill tube, the tube I3 is unscrewed from the fitting 33 and the cylinder 56 unscrewed from the fittings 38 and 59. The piston 51 is pushed down and the pin 53 is tted into the bore 52 and in the bore 5I of the rod 49, thus pushing the ball check valve from its seat. The ball check valve 3Q is on its seat. By withdrawing the piston the line is straightened but not suilicient to withdraw the pin 53 from the bore 51. The tube 55 is then screwed into the fitting 33. The

piston is pushed down to its lowermost position. Due to the concave chamber on the underneath side of the piston, the flexible line coils up underneath the piston. The fitting 55, connected to the tube 8| and fitting 83, is screwed into the tube 55. Both or" the plugs 65 are removed and water or other liquid is pumped through ports 64 into the tube 56 above the piston. The tube 55 is thus iilled with water until it passes out of the other open port 56. The water or other iluid thus stands at a level to subinerge the choke 5I with atmospheric pressure in chamber 82. The plugs 55 are then replaced. Plug I5 is removed and the clock set to close contact after a predetermined lapse of time. The plug is replaced, the cylinder I3 screwed into the fitting 35 and the device is thus charged and ready for ilisertion into the drill pipe after removal of the elly.

As has been indicated previously, the sampling tube is circulated to bottom with the bit 2 ofi bottom about two feet. The sampler which passes down through the pipe I seats in the position shown in Figs. l, 2, and 4.

It will be noted that since the frangible tube 2| is closed, the sample-receiving container and all portions of the sampler above the tube are sealed from the mud in the Well. The cylinder 8l is positioned on top of the fitting 59 and the wedge 1I is in the position shown in Fig. 4, per mitting the spring 16 to push the latches 13 into the recess 88 of the drill pipe underneath the fitting 89 in the drill pipe.

It will be observed that such recesses are convehtional in wire line core barrel drills and thus sampler may be employed with an ordinary wire line core barrel. Thus, when it is desired to core as well as sample, wire line core barrel ecring maybe carried on as is conventional. When it is desired to sample the wire line core barrel may be removed and the sampler introduced in its place. By setting the sample-receiving tube 56 below the Vlatch and the balancing fluid-receiving tube 8| above the latch, it is possible to have a sample-receiving tube of maximum volume, as is permitted by the interval between the latches and the core bit 2 provided by conventional core barrel construction.

v'1"he sampler, having reached bottom, is seated on shoulder I2, as is indicated, by a rise in mud pressure, the weight of the drill pipe or that portion thereof as may be desired, as will `be directed by good drilling techniques and as will be understood by those skilled in the art, may then be positioned on the latches and the sampling core tube 4. As is conventional, the rotative power `is transmitted from the drill pipe I to the latches 13 by a shoulder or projection which is positioned in the recess 88, as is conventional in wire line core barrel operations and is not illustrated above. Coring is continued by rotat ing and advancing the drill pipe. The coring tube 4 is drilled into the formation, a core enter- .ing .the tube 4. TheV mud above the core is displaced through the `perforation 6 in the portion. of the tube core 4. The `core tube is drilled into the formation until the bit 2 reaches bottom, as will be signalled by reduction in load on the weight indicator conventionally employed in f drilling. The teeth 5 of core tube 4 are offset so as to cut a slight clearance between the core in the tube 4 and the walls thereof and between the tube 4 and the formation. This will permit mud trapped in 4 and 8 above the core in 4 to escape between the core and wall of 4. Drilling is then interrupted.

During drilling operations mud descends through tube I, around sampler 3, through the annulus 9i! surrounding the sampler, and out the port SI conventionally present in core bits. The mud present in the core tube above the core is Ydisplaced by the entering core and acts to lubricate the core tube. As the sampler core tube 4 is drilled into the formation the coring tube 4 enters the formation and the tube 8 is also drilled in, compacting the formation underneath 9 and around the wall 1 to form a seal which seals the outside of the tube 4 in the formation. As is usual, the bottom of the bore is wetted by the mud a couple of inches and yis relatively plastic. VThe wedging action of the bevel 9 compresses this portion of the formation tightly around the tube 4 sealing the clearance which has been cut. The tube 4 is thus sealed in the formation against mud 'infiltration and against escape of formation fluid around the tube 4. A core is thus drilled and positioned inside the drill sampling tube 4. This core, because of vthe set of the core `teeth on l4, kis smaller in diameter than the inside of 'tube 4.

Formation fluid passes around this core into the chamber Ill and cannot pass further because of the sealing tube 2I. Drilling having stopped and circulation interrupted, the clock 32 having been set for a predetermined time, suillcient to .permit the ,aboveoperations to be performed, the clock arm 33 closes contact on 34 and connects the detonating cap in the charge .23 to the batteries 30 and the charge 'is exploded, fracturing the tube 2 I. Communication is now established between the tube 4 and the conduit 2D. Formation fluid enters through perforations 6 and passes upward through tube 4, conduit I0, con duit 2U, port I9, and the annular recess 92 surrounding the clock chamber I4, Fluid passes into the chamber 31 flowing past the valve 39 lifting the ball check valve 40 oil its seat, flowing through the seat .54, entering cylinder 56 under neath the piston 51, lifting the piston.

The rate of ascent of the piston is determined by the rate of passage of fluid from above the piston through the choke 6I and through the conduit $1 into the chamber 82. The pressure on the entering fluid is at all times maintained in equilibrium with formation pressure. This is accomplished by making the choke 6I small. being a needle hole and being replaceable so that vthe size of the orifice can be adjusted. I can thus maintain the pressure differential above and below the piston relatively low. This piston moves relatively slowly in the cylinder 56 since it cannot move more rapidly than the escape of fluid through the choke. Since the piston moves slowly and fluid from the formation can move no more rapidly than the flow of fluid through the choke and the rate of ascent of the piston, the velocityr of the formation fluid entering the sampling chamber is low, resulting in but a small pressure drop due to friction, with little pressure loss for the reason that the fluid entering underneath the piston is substantially at formation pressure. A true sample without phase separation is taken. This sampling `is then con-- tinued until the piston 51 reaches the top of its travel, at which time it seats against the bottom of the fitting 59 sealing on? the chamber underneath the piston 51. The piston, making a fluidtight seal, maintains the fluid underneath the piston at its formation pressure and prevents both its escape and the contamination by the fluid above the piston. The fluid which is thus discharged through the choke orifice BI passes up the coil pipe 61 through the tube 82 and into the chamber 82 where it compresses the air in this chamber. When the piston is against the plug fitting 38, the air pressure in 82, above the fluid in 82, is substantially less than formation pressure.

In this position the wire 58 has been extended and the pin 53- withdrawn into the chamber beneath the piston 51. The valve 49' seats, due to the spring action, thus closing oil the end of the sampling cylinder and preventing the entry of additional fluid from the bore hole, regardless of higher pressures that may be encountered in the bore hole when the sampling tube is withdrawn from the formation. The pin acts as a trigger which is released by extension of the string. The drill pipe is lifted off bottom, the pipe set in slips, and the kelly removed. The

y, sample may now be withdrawn by introducing the grapple 81 of the overshot, which is lowered on a wire line from the surface until it engages the head 86. Tension placed upon the wire then first elevates the cylinder SI, withdrawing the rod 10, extending the coiled helical tube .61 and engaging the wedge 1I with the beveled portion 18 of the latches 13 and moving the latches into disengaged position shown in Fig. 5. The shoulder 1I on the rod 10 abuts the depending shoulder 11, and further lifting lifts the entire sampler assembly. The sampler containing the lluid sample and the core in tube 4 are returned to the surface.

The sampler is opened by unscrewing cylinder I3 from the fitting 38. The fitting 38 may then be screwed into a container suitable to receive and hold the iiuid pressure with suitable provisions for unseating the valve 39. When valve 39 is open a very small pressure within the sample container will unseat ball check valve 49 and permit removal of fluid. Plug 65 may be removed and water or other fluid under pressure pumped into the cylinder 56 above the piston 51 to force the piston down.

While I have described a particular embodiment of my invention for the purpose of illustration, it should be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

I claim:

1. A formation sampler comprising an upper chamber, a top and bottom closure for said chamber, a tube, one end of said tube connected to said lower closure and to said chamber, a conical wedge on the other end of said tube, a flexible tube connected to said mst-mentioned tube, a latch fitting comprising a plurality of hinged links in operative engagement with said wedge, a motion-limiting stop on said rstmentioned tube, a second chamber, the other end of said fiexible tube being connected to the top of said second chamber, a freeiy sliding piston in said second chamber, closable ports connecting the exterior of said second chamber to the top of said chamber, a valve closure at the bottom of said second chamber, said valve comprising a check valve, a trigger' in operative association with said valve, a string connected to said trigger and said piston, said string operating said trigger on extension of said string, a sampler core bit connected to said valve, a frangible tube closure separating said core tube from said valve, an explosive charge in said tube, and timeactuated electrical means for exploding said charge mounted in said sampler.

2. A formation sampler comprising an upper chamber, a top and bottom closure for said chamber, a tube, one end of said tube connected to said lower closure and to said chamber, a conical wedge on the other end of said tube, a flexible tube connected to said first-mentioned tube, a latch fitting comprising a plurality of hinged links in operative engagement with said wedge, a motion-limiting stop on `said firstmentioned tube, a second chamber, the other end of said flexible tube being connected to the top of said second chamber, a freely sliding piston in said second chamber, closable ports connecting the exterior of said second chamber to the top of said chamber, a valve closure at the bottom of said second chamber, said valve comprising a check valve, a trigger in operative association with said valve, a string connected to said trigger and said piston, said string operating said trigger on extension of said string, a core tube receiving conduit connected to said valve, said conduit having an end having a downwardly beveled end, a core sampling tube connected to said core tube receiving conduit having an external diameter less than the external diameter of said core tube receiving conduit and forming a conical annulus with the end of said core tube receiving conduit, a frangible tube mounted in said core tube receiving conduit and closing said conduit, an explosive charge mounted in said tube. and time-controlled electrical means for exploding said charge mounted in said sampler.

3. A bore hole formation sampler comprising a housing adapted to be introduced into a bore hole, a fluid sample-receiving chamber in said housing, a travelling piston in said chamber, a sampling tube mounted on said housing and adapted to be fluidly coupled with a formation to be sampled, a fluid channel in said housing for providing a fluid conducting passageway between said sampling tube and said chamber on one side of said piston means normally preventing the entrance of fluid through said sampling tube into said channel, means for disabling said last-mentioned means when said sampling tube is iiuidly coupled with a formation to be sampled, whereby fluid from said formation passes through said channel into said chamber and displaces said traveling piston, a normally-open valve in said channel, closing means in said housing for closing said valve, and means coupling said piston and said closing means for eifectuating closure of said valve after a predetermined displacement of said piston.

4. A bore hole formation sampler comprising a housing adapted to be introduced in a bore hole, a fluid sample-receiving chamber in said housing, a travelling. piston in said chamber, a sampling tube mounted on said housing and adapted to be inserted into the formation to be sampled, a fluid channel in said housing for providing a fluid yconducting passageway between said sampling tube and said chamber on one side of said piston, a frangible closure in said channel, means for rupturing said frangible closure when said sampling tube is inserted into a formation whereby fluid from said formation passes through said channel into said chamber and displaces said ltraveling piston, a normallyopen valve in said channel, closing means in said housing for closing said valve, and means coupling said piston and said closing means for effectuating closure of said valve after a predetermined displacement of said piston.

5. A bore hole formation sampler comprising a housing adapted to be introduced in a bore hole, a fluid sample-receiving chamber in said housing, a travelling piston in said chamber, a sampling tube mounted on said housing and adapted to be inserted into the formation to be sampled, a fluid channel in said housing for providing a iiuid conducting passageway between said sampling tube and said chamber on one side of said piston, a closure positioned in said channel, means for opening said closure to effect free communication of fluid through said channel into said chamber whereby said traveling piston is displaced, a spring-operated valve means in said channel, retaining means normally retaining said valve means in the open position under tension, and means coupling said retaining means to said piston for releasing said valve means after a predetermined displacement of said piston thereby closing said channel.

6. A bore hole formation sampler comprising a housing adapted to be introduced through drill pipe, a fluid sample-receiving chamber in said housing, a travelling piston in said chamber, a rotary core tube affixed beneath said housing, a fluid channel in said housing providing a fluid conducting passageway between said core tube and said chamber on one side of said piston, a frangible closure in said channel, means for iatchmg said housing in said drm pipe into which said housing is introduced, whereby said core tube projects beyond the end of said drill pipe, means for rotating said housing and core tube upon the rotation of said drill pipe whereby said core tube is drilled into a formation to be sampled, means for rupturing said frangible closure Iwhen said tube is in said formation whereby fluid from said formation passes through said channel into said chamber and displaces said traveling,- piston, a normally-open valve in said channel, closing means in said housing for closing said valve, means coupling said piston and said closingr means for eectuating closure of said valve after a predetermined displacement Il0 of said piston, and means for unlatching said housing from said drill pipe.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,201,447 Mullins May 21, 1940 2,256,552 Drake Sept. 23, 1941 2,332,813 Rolshausen et al. Oct. 26, 1943 2,418,500 Chambers Apr. 8, 1947 2,528,981 Stokes Nov. 7, 1950 2,545,306 Pollard, Jr Mar. 13, 1951 

